usb2514b-aezc-tr

The USB2514B-AEZC-TR is a 4-port USB 2.0 Hi-Speed hub controller manufactured by Microchip Technology, belonging to the USB251xB family. It leverages Microchip’s innovative MultiTRAK technology, which provides one transaction translator per downstream port, delivering industry-leading data throughput in mixed-speed USB environments where Hi-Speed, Full-Speed, and Low-Speed devices are connected simultaneously.

The controller supports all three USB 2.0 data rates: 480 Mbps (Hi-Speed), 12 Mbps (Full-Speed), and 1.5 Mbps (Low-Speed). It operates from a single 3.3V supply with internal 1.2V regulators for core logic, and draws approximately 70 mA typical operating current. The device is fully compliant with the USB 2.0 specification and supports USB Battery Charging specification Rev. 1.1 for Charging Downstream Ports (CDP).

Key features include PortMap for flexible port mapping and disable sequencing, PortSwap for programmable USB differential-pair pin locations to simplify PCB layout, and PHYBoost for programmable USB signal drive strength with 4-level resolution to recover signal integrity. The device integrates all USB termination and pull-up/pull-down resistors, supports an onboard 24 MHz crystal driver or external 24/48 MHz clock input, and allows customizable Vendor ID, Product ID, and Device ID via I2C EEPROM or SMBus slave interface.

The USB2514B-AEZC-TR provides 4 kV HBM ESD protection (JESD22-A114F) in both powered and unpowered states, supports self-powered or bus-powered operation, and offers full power management with individual or ganged power control of each downstream port. The -AEZC-TR suffix indicates extended commercial temperature range (0°C to +85°C), QFN package, and tape and reel packaging.

The USB2514B-AEZC-TR operates as a USB 2.0 Hi-Speed hub controller, expanding a single upstream USB port into four downstream ports with full USB 2.0 compliance.

Upstream Connection: The controller connects to the USB host (upstream) through a differential USB transceiver pair (D+/D-). It negotiates the highest possible speed with the host (up to 480 Mbps Hi-Speed) and handles all USB protocol-level communication including device enumeration, configuration, and power management.

MultiTRAK Transaction Translation: The core innovation is the per-port transaction translator (TT) architecture. In a mixed-speed environment where Hi-Speed and Full-/Low-Speed devices coexist, each downstream port has its own TT. This eliminates the bottleneck of a single shared TT (found in single-TT hubs), allowing Full-Speed and Low-Speed transactions to proceed in parallel across ports without blocking Hi-Speed traffic on other ports.

Downstream Port Management: Each of the four downstream ports implements a full USB 2.0 transceiver with integrated termination resistors. The controller manages port power switching (individual or ganged), over-current detection, and port enable/disable sequencing per the PortMap configuration. The PortSwap feature allows the physical location of D+ and D- pins to be swapped in firmware, enabling direct PCB trace routing to USB connectors without vias or trace crossings.

Configuration and Customization: At power-up, the device reads configuration from an I2C EEPROM (or via SMBus slave interface). This allows OEMs to customize Vendor ID, Product ID, device descriptors, port mapping, power settings, and PHYBoost drive strength levels without changing hardware. If no EEPROM is present, the device operates with default settings.

PHYBoost Signal Integrity: The PHYBoost feature provides 4-level programmable USB signal drive strength per port. In designs with long PCB traces or connectors that degrade signal integrity, the drive strength can be increased to compensate, eliminating the need for external signal conditioning components.

Power Management: The controller supports both bus-powered and self-powered hub configurations. In bus-powered mode, it enforces USB power budget limits. Individual port power control allows selective port shutdown for power savings. The device also supports USB Battery Charging 1.1 CDP mode, where downstream ports can provide up to 1.5 A charging current while simultaneously supporting data transfer.

Clock Architecture: The device includes an on-chip 24 MHz crystal oscillator driver. A low-cost 24 MHz crystal or ceramic resonator provides the reference clock. Alternatively, an external 24 MHz or 48 MHz clock can be fed directly. Internal PLLs multiply the reference to generate the 480 MHz and other internal clock domains required for Hi-Speed USB operation.